MoS2/Reduced Graphene Oxide Aerogel Composite for Lithium Ion Battery Anodes

Abstract

As well known, the increasing consumption of fossil fuel and the consequent environment problems, energy storage has become a global concern. The rechargeable batteries with high capacity, low cost and long cycling life is highly desired for large-scale applications in the future. 1 In the past decade, rechargeable lithium ion batteries (LIBs) have attracted considerable attention for their various advantages, such as high specific capacity, high voltage, long cycle life, and low self-discharge. These features make LIBs to be ideal power source for portable electronic devise and electric vehicles (EVs). 2Nevertheless, LIBs are encountering the next-level energy storage demand on further increase of energy density, operation safety and cycle life for EVs and smart grid energy technologies. 1 One hinder is the low specific capacity of the traditional graphite anode materials. Great efforts have been made to develop suitable anode materials with both high capacity and safety. Recently, transition metal sulfides have emerged as promising electrode materials for LIBs because of their high specific capacity, low cost, and other unique properties. Particularly, molybdenum disulfide (MoS2), a representative 2D material which delivers a similar structure to graphene, has been actively investigated owing to its high specific capacity (669 mAh g-1) from the four-electron transfer reaction, MoS2+4Li+4e→Mo+2Li2S. However, MoS2 still suffers from the inherent low electrical conductivity and large inherent volume change, which will result in poor cycling stability and rate property. 3 To address these drawbacks, one of the most effective strategies is to combine MoS2 with conductive carbon-based materials, such as porous carbon, carbon nanotubes and graphene. 4 Herein, the MoS2 nanosheets has been successfully grown on reduced graphene oxide (r-GO) aerogel with a one-pot hydrothermal method. The prepared MoS2 nanosheets show a strong interaction with the r-GO aerogel substrate which could provide strong combination and facile electron transport between the MoS2 and r-GO substrate. The unique structure of the composite which could remain the high capacity of the MoS2 and the high conductivity of the r-GO aerogel. This synergy effects makes the MoS2/r-GO composite exhibits excellent lithium storage performance with high capacity (950 mAh g-1 at 0.05 A g-1), good cyclic stability ( about 600 mAh g-1 at 200 cycles). Figure captions Figure 1. (a) Charge-discharge profiles of MoS2/r-GO composites. (b) Cycling performances at the current density of 0.05 A g-1 and 100 mA g-1. References Zhang, Z.; Zhao, H.; Teng, Y.; Chang, X.; Xia, Q.; Li, Z.; Fang, J.; Du, Z.; Świerczek, K., Carbon-Sheathed MoS2 Nanothorns Epitaxially Grown on CNTs: Electrochemical Application for Highly Stable and Ultrafast Lithium Storage. Advanced Energy Materials 2017, 8 (7), 1700174.Qin, W.; Li, Y.; Teng, Y.; Qin, T., Hydrogen bond-assisted synthesis of MoS2/reduced graphene oxide composite with excellent electrochemical performances for lithium and sodium storage. Journal of Colloid and Interface Science 2018, 512, 826-833.Zhang, X. Q.; Li, X. N.; Liang, J. W.; Zhu, Y. C.; Qian, Y. T., Synthesis of MoS2@C Nanotubes Via the Kirkendall Effect with Enhanced Electrochemical Performance for Lithium Ion and Sodium Ion Batteries. Small 2016, 12 (18), 2484-2491.Xia, S.; Wang, Y.; Liu, Y.; Wu, C.; Wu, M.; Zhang, H., Ultrathin MoS2 nanosheets tightly anchoring onto nitrogen-doped graphene for enhanced lithium storage properties. Chemical Engineering Journal 2018, 332, 431-439. Figure 1